because i don't know, what the better list, i sent this mail to the
firewall and ipv6 mailinglist - i hope this is OK.

i am administrate a debian firewall since 2 years without problems. this
weeks, we want to activate IPv6 in testing mode. out firewall script are
generated with fwbuilder. after i have activated IPv6 on our firewall, i
run into some troubles. the first one was, the radvd wasn't able to send
advertisement multicasts (radvd log: operation not permitted). first i
ignored this problem and i tested ping6 between the hosts and the
firewall with the FE80:: addresses. this wasn't also working. after 2
days debugging and searching the error, i found out the following:

fwbuilder generates at the top of the FW script this rules, when the
option 'Drop packets that are not associated with any known connection'
is active: